Full Description

"Let us consider the results of investigation of diur nal acoustic activity of fish. Figure 2 demonstrates the diagrams of changes of acoustic activity of salmons (chum salmon and pink salmon) during 24 hours. The diurnal distribution of sounds shows certain cyclicity. It is seen in the plots that the maximum number of sounds of salmons was recorded at twilight. There were two peaks of acoustic activity of chum salmon and pink salmon: in the evening from 10 p.m. to 2 a.m. with some alleviation at midnight and in the daybreak from 6 to 10 a.m."

"Duration of signals of pink salmon by the analogue outlet is 420–800 ms. The amplitude modulation of signals with a frequency of 24–40 Hz is present. As a rule, the spectra of signals from pink salmon contain two maxima of energy in subranges of frequencies 200–400 Hz and 420–950 Hz. Dynamic spectra of some signals from pink salmon are charac terized by the shift of energies in these frequency sub ranges, by their fusion, and subdivision during one sig nal."

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Observation Environment Quotes

"Sounds were recorded in 7 _ 2.5 _ 3 m and 10 _ 4 _ 7 m cages at the sea depth of 7 m and in open water bodies in places of the densest aggregation of the investigated fish – in the Peter the Great Bay (Pri mor’e Territory), off Kunashir Island, and in the Aniva Bay (Sakhalin oblast)."

Sound Name Quotes

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Full Description

"The maximum of acoustic activity of herring and sardines also occurs in the dark part of the day (Fig. 3). In contrast to salmons, they have a monophasic type of diurnal distribution of sounds and sounding of objects is more distinct, obviously depending on a higher density of fish in the registration place. The quantity of emitted sounds increases at twilight; the movements of herring and sardines in the cage have a clear coordination of all individuals in the school in the daytime and become chaotic at twilight, often fish jump to the surface."

"The cyclicity of diurnal acoustic activity of sardines and herring is recorded both at cage keeping and under natural conditions of the body of open water."

"The amplitudetemporal and spec tral characteristics of signals from sardines and herring are generally similar. Duration of signals by the ana logue outlet is 600–1200 ms. The amplitude modula tion is 45–55 Hz. The spectra have a developed dynamic structure, with the most intensive compo nents within subranges of frequencies 380–850 Hz and 800–2000 Hz. Dynamics of the behavior of the spectra of some signal s from sardines has a rather complicated structure. Fig. 4d shows the amplitude temporal characteristic and dynamic spectrum of such a signal. At the initial part of the signal the spectrum has wideband discrete rows with central frequencies 210 Hz (68 dB), 880 Hz (70 dB), 1470 Hz (70 dB), and 1880 Hz (72 dB). In another part of the signal the spectral energy is redistributed into subranges of fre quencies 360–850 Hz and 1100–2200 Hz with the maximum energy in central frequencies: 470 Hz (82 dB) and 1440 Hz (75 dB)."

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Observation Environment Quotes

"Sounds were recorded in 7 _ 2.5 _ 3 m and 10 _ 4 _ 7 m cages at the sea depth of 7 m and in open water bodies in places of the densest aggregation of the investigated fish – in the Peter the Great Bay (Pri mor’e Territory), off Kunashir Island, and in the Aniva Bay (Sakhalin oblast)."

Sound Name Quotes

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Full Description

"Let us consider the results of investigation of diur nal acoustic activity of fish. Figure 2 demonstrates the diagrams of changes of acoustic activity of salmons (chum salmon and pink salmon) during 24 hours. The diurnal distribution of sounds shows certain cyclicity. It is seen in the plots that the maximum number of sounds of salmons was recorded at twilight. There were two peaks of acoustic activity of chum salmon and pink salmon: in the evening from 10 p.m. to 2 a.m. with some alleviation at midnight and in the daybreak from 6 to 10 a.m."

"Duration of signals of chum salmon by the analogue outlet varies in wide limits: 250– 1750 ms. Spectral analysis of signals demonstrated that most recorded sounds, irrespective of the form of the signal are characterized by the presence of two clear maxima of spectral energy. The main energy of signals is concentrated in two frequency subranges 100–330 Hz and 450–740 Hz. Redistribution of energy from the beginning to the end of the signal by a frequency within these subranges is possible. There is an amplitude modulation of signals with a frequency 6–14 Hz."

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Observation Environment Quotes

"Sounds were recorded in 7 _ 2.5 _ 3 m and 10 _ 4 _ 7 m cages at the sea depth of 7 m and in open water bodies in places of the densest aggregation of the investigated fish – in the Peter the Great Bay (Pri mor’e Territory), off Kunashir Island, and in the Aniva Bay (Sakhalin oblast)."

Sound Name Quotes

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

Full Description

"The maximum of acoustic activity of herring and sardines also occurs in the dark part of the day (Fig. 3). In contrast to salmons, they have a monophasic type of diurnal distribution of sounds and sounding of objects is more distinct, obviously depending on a higher density of fish in the registration place. The quantity of emitted sounds increases at twilight; the movements of herring and sardines in the cage have a clear coordination of all individuals in the school in the daytime and become chaotic at twilight, often fish jump to the surface."

"The cyclicity of diurnal acoustic activity of sardines and herring is recorded both at cage keeping and under natural conditions of the body of open water."

"The sound from herring have wide band and dynamic spectra. The principal energy of most signals is concentrated in subranges of frequen cies 320–800 Hz and 1000–1800 Hz. The dynamics of the spectra are characterized mainly by redistribution of energy of the second frequency subrange of signals of various phonetic groups. The duration of signals is 650–980 ms. Frequency of the amplitude modulation of biosignals is 35–55 Hz."

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

"As a result of this, the consequent series of pulse and resonance oscillations of bubbles create chirping signals from herring with the decreasing frequency of emission within each pulse series."

Observation Environment Quotes

"Sounds were recorded in 7 _ 2.5 _ 3 m and 10 _ 4 _ 7 m cages at the sea depth of 7 m and in open water bodies in places of the densest aggregation of the investigated fish – in the Peter the Great Bay (Pri mor’e Territory), off Kunashir Island, and in the Aniva Bay (Sakhalin oblast)."

Sound Name Quotes

"Dynamic spectra of sounds are concentrated in two subranges of frequen cies in accordance to each fish species: chum salmon – 100–200 Hz and 450–700 Hz (98 ± 4 dB/20 µP/1 m); pink salmon – 250–350 Hz and 600–900 Hz (92 ± 2 dB); herring – 350–500 Hz and 800–1200 Hz (82 ± 2 dB); and sardines – 400–550 Hz and 1000–1400 Hz (78 ± 3 dB). It is possible to point out the following regularities of formation of signals in the investigated physostomous fish: (1) these are lowfrequency oscillations up to 2 kHz with clear frequency components in the spec trum zones corresponding to each object; (2) this is a similarity of a certain form of spectra and dependence of the frequency composition of sig nals on the size of the soundemitting object (shift of spectral energy to the region of higher frequencies, the decrease of signal levels with decreasing fish size), and the frequency modulation in the corre sponding zones of the spectrum from the beginning to end of the signal; (3) high levels of acoustic pressure at dominant fre quencies (up to 8 Pa/m) and a characteristic pulse structure of signals with an exponential decrease of the amplitude in pulses."

"As a result of this, the consequent series of pulse and resonance oscillations of bubbles create chirping signals from herring with the decreasing frequency of emission within each pulse series."